Morton's metatarsalgia is a condition associated with a painful neuroma* on the digital nerve causing pain in the foot. Charcterised by perineural fibrosis and nerve degeneration due to repetitive irritation, is thought to be due to irritation of the digital nerve caused by repeated trauma, ischemia or entrapment of the nerve, occurs most frequently in women aged 40-50 who wear high-heeled, pointed-toe shoes. The neuroma occurs at the level of the metatarsal necks. The common digital nerve to the third/fourth metatarsal spaces is most often affected, although other interspaces can be involved.
Morton's Neuroma is a caused by pressure, abnormal function/motion or an imbalance in the structure of the foot such as flat feet, that causes an abnormal pressure on the structures and the nerves in the ball of the foot. It most commonly affects the nerve that goes to the 2nd 3rd or 4th toes. The squeezing of the nerve from abnormal motion leads to a protective thickening of the sheath that protects the nerve. Symptoms of Morton's Neuroma often occur during or after activities that cause a sidewards squeezing of the ball of the foot or from pressure such as walking, standing, or playing sport. Since squeezing is a common cause of the condition, shoes such as pointed toes or high heels can often lead to a neuroma. Shoes that are constricting, even tight sneakers, can pinch the nerve between the toes, causing inflammation and pain.
Neuroma pain is classically described as a burning pain in the forefoot. It can also be felt as an aching or shooting pain in the forefoot. Patients with this problem frequently say they feel like they want to take off their shoes and rub their foot. This pain may occur in the middle of a run or at the end of a long run. If your shoes are quite tight or the neuroma is very large, the pain may be present even when walking. Occasionally a sensation of numbness is felt in addition to the pain or even before the pain appears.
X-rays of your affected foot will not show a neuroma, as neuromas are made up of soft tissue. X-rays may be helpful, however, in helping rule in osteoarthritis or a stress fracture as the cause of your symptoms. Ultrasonography and MRI are sometimes used to help diagnose neuromas, although they are often ineffective. The clinical diagnosis by a foot care expert with experience treating this health problem is usually the most effective way to diagnose neuromas. Your podiatrist will attempt to duplicate your neuroma symptoms by pressing on the involved nerve at various points, and he or she may try to cause a clicking of your nerve that indicates nerve enlargement.
Non Surgical Treatment
If symptoms are severe or persistent and self-help measures did not help, the doctor may recommend corticosteroid injections, a steroid medication that reduces inflammation and pain is injected into the area of the neuroma. Only a limited number of injections are advised, otherwise the risk of undesirable side effects increases, including hypertension (high blood pressure) and weight gain. Alcohol sclerosing injections, studies have shown that alcohol injections reduce the size of Morton's neuromas as well as alleviating pain. This is a fairly new therapy and may not be available everywhere. The doctor injects alcohol in the area of the neuroma to help sclerose (harden) the nerve and relieve pain. Injections are typically administered every 7 to 10 days. For maximum relief 4 to 7 injections are usually needed.
The ultimate success of a Morton?s neuroma treated surgically is somewhat unclear. This is likely due to the idea that in most instances a ?Morton?s neuroma? is actually more than just an isolated nerve problem but rather consitutes a metatarsalgia where other structures (such a as the MTP joints) are also problematic, not just the nerve. Therefore, addressing the nerve as well as the other components of a metatarsalgia may offer a better chance of surgical success. However, like many conditions in foot and ankle, it is ideal if this condition can be managed without surgery.